diff --git a/crates/hir-def/src/nameres.rs b/crates/hir-def/src/nameres.rs
index 0ab1bd8490..e7a4355d25 100644
--- a/crates/hir-def/src/nameres.rs
+++ b/crates/hir-def/src/nameres.rs
@@ -60,7 +60,7 @@ mod tests;
 use std::{cmp::Ord, ops::Deref};
 
 use base_db::{CrateId, Edition, FileId, ProcMacroKind};
-use hir_expand::{name::Name, InFile, MacroCallId, MacroDefId};
+use hir_expand::{name::Name, HirFileId, InFile, MacroCallId, MacroDefId};
 use itertools::Itertools;
 use la_arena::Arena;
 use profile::Count;
@@ -626,6 +626,17 @@ impl ModuleData {
         self.origin.definition_source(db)
     }
 
+    /// Same as [`definition_source`] but only returns the file id to prevent parsing the ASt.
+    pub fn definition_source_file_id(&self) -> HirFileId {
+        match self.origin {
+            ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition } => {
+                definition.into()
+            }
+            ModuleOrigin::Inline { definition, .. } => definition.file_id,
+            ModuleOrigin::BlockExpr { block } => block.file_id,
+        }
+    }
+
     /// Returns a node which declares this module, either a `mod foo;` or a `mod foo {}`.
     /// `None` for the crate root or block.
     pub fn declaration_source(&self, db: &dyn DefDatabase) -> Option<InFile<ast::Module>> {
diff --git a/crates/hir/src/has_source.rs b/crates/hir/src/has_source.rs
index 9f6b5c0a9f..63d11155c6 100644
--- a/crates/hir/src/has_source.rs
+++ b/crates/hir/src/has_source.rs
@@ -1,12 +1,13 @@
 //! Provides set of implementation for hir's objects that allows get back location in file.
 
+use base_db::FileId;
 use either::Either;
 use hir_def::{
     nameres::{ModuleOrigin, ModuleSource},
     src::{HasChildSource, HasSource as _},
     Lookup, MacroId, VariantId,
 };
-use hir_expand::InFile;
+use hir_expand::{HirFileId, InFile};
 use syntax::ast;
 
 use crate::{
@@ -32,6 +33,11 @@ impl Module {
         def_map[self.id.local_id].definition_source(db.upcast())
     }
 
+    pub fn definition_source_file_id(self, db: &dyn HirDatabase) -> HirFileId {
+        let def_map = self.id.def_map(db.upcast());
+        def_map[self.id.local_id].definition_source_file_id()
+    }
+
     pub fn is_mod_rs(self, db: &dyn HirDatabase) -> bool {
         let def_map = self.id.def_map(db.upcast());
         match def_map[self.id.local_id].origin {
@@ -40,6 +46,16 @@ impl Module {
         }
     }
 
+    pub fn as_source_file_id(self, db: &dyn HirDatabase) -> Option<FileId> {
+        let def_map = self.id.def_map(db.upcast());
+        match def_map[self.id.local_id].origin {
+            ModuleOrigin::File { definition, .. } | ModuleOrigin::CrateRoot { definition, .. } => {
+                Some(definition)
+            }
+            _ => None,
+        }
+    }
+
     pub fn is_inline(self, db: &dyn HirDatabase) -> bool {
         let def_map = self.id.def_map(db.upcast());
         def_map[self.id.local_id].origin.is_inline()
diff --git a/crates/ide-completion/src/completions/mod_.rs b/crates/ide-completion/src/completions/mod_.rs
index d3e75c6da4..1e09894059 100644
--- a/crates/ide-completion/src/completions/mod_.rs
+++ b/crates/ide-completion/src/completions/mod_.rs
@@ -42,7 +42,7 @@ pub(crate) fn complete_mod(
     }
 
     let module_definition_file =
-        current_module.definition_source(ctx.db).file_id.original_file(ctx.db);
+        current_module.definition_source_file_id(ctx.db).original_file(ctx.db);
     let source_root = ctx.db.source_root(ctx.db.file_source_root(module_definition_file));
     let directory_to_look_for_submodules = directory_to_look_for_submodules(
         current_module,
diff --git a/crates/ide-db/src/search.rs b/crates/ide-db/src/search.rs
index e8ff107bd4..16f3598183 100644
--- a/crates/ide-db/src/search.rs
+++ b/crates/ide-db/src/search.rs
@@ -149,10 +149,8 @@ impl SearchScope {
 
         let mut to_visit: Vec<_> = module.children(db).collect();
         while let Some(module) = to_visit.pop() {
-            if let InFile { file_id, value: ModuleSource::SourceFile(_) } =
-                module.definition_source(db)
-            {
-                entries.insert(file_id.original_file(db), None);
+            if let Some(file_id) = module.as_source_file_id(db) {
+                entries.insert(file_id, None);
             }
             to_visit.extend(module.children(db));
         }
diff --git a/crates/ide/src/static_index.rs b/crates/ide/src/static_index.rs
index 3e3d9f8f85..03c7ee478a 100644
--- a/crates/ide/src/static_index.rs
+++ b/crates/ide/src/static_index.rs
@@ -187,7 +187,7 @@ impl StaticIndex<'_> {
     pub fn compute(analysis: &Analysis) -> StaticIndex<'_> {
         let db = &*analysis.db;
         let work = all_modules(db).into_iter().filter(|module| {
-            let file_id = module.definition_source(db).file_id.original_file(db);
+            let file_id = module.definition_source_file_id(db).original_file(db);
             let source_root = db.file_source_root(file_id);
             let source_root = db.source_root(source_root);
             !source_root.is_library
@@ -201,7 +201,7 @@ impl StaticIndex<'_> {
         };
         let mut visited_files = FxHashSet::default();
         for module in work {
-            let file_id = module.definition_source(db).file_id.original_file(db);
+            let file_id = module.definition_source_file_id(db).original_file(db);
             if visited_files.contains(&file_id) {
                 continue;
             }
diff --git a/crates/rust-analyzer/src/cli/analysis_stats.rs b/crates/rust-analyzer/src/cli/analysis_stats.rs
index 01bc0d77dd..9d6c633f4c 100644
--- a/crates/rust-analyzer/src/cli/analysis_stats.rs
+++ b/crates/rust-analyzer/src/cli/analysis_stats.rs
@@ -105,7 +105,7 @@ impl flags::AnalysisStats {
         }
         for krate in krates {
             let module = krate.root_module(db);
-            let file_id = module.definition_source(db).file_id;
+            let file_id = module.definition_source_file_id(db);
             let file_id = file_id.original_file(db);
             let source_root = db.file_source_root(file_id);
             let source_root = db.source_root(source_root);
diff --git a/crates/rust-analyzer/src/cli/diagnostics.rs b/crates/rust-analyzer/src/cli/diagnostics.rs
index 4306d72129..0b46f35074 100644
--- a/crates/rust-analyzer/src/cli/diagnostics.rs
+++ b/crates/rust-analyzer/src/cli/diagnostics.rs
@@ -37,14 +37,14 @@ impl flags::Diagnostics {
         let mut visited_files = FxHashSet::default();
 
         let work = all_modules(db).into_iter().filter(|module| {
-            let file_id = module.definition_source(db).file_id.original_file(db);
+            let file_id = module.definition_source_file_id(db).original_file(db);
             let source_root = db.file_source_root(file_id);
             let source_root = db.source_root(source_root);
             !source_root.is_library
         });
 
         for module in work {
-            let file_id = module.definition_source(db).file_id.original_file(db);
+            let file_id = module.definition_source_file_id(db).original_file(db);
             if !visited_files.contains(&file_id) {
                 let crate_name =
                     module.krate().display_name(db).as_deref().unwrap_or("unknown").to_string();